1. Field of the Invention
The present invention relates to connection members by which secondary cells served as an electric source for driving a hybrid vehicle etc. are integrated into a module, as well as a battery pack using the connection members.
2. Description of the Related Art
In a battery pack, a plurality of secondary cells are disposed side by side in order to obtain a required output. A casing partitioned into a plurality of sub-chambers is used so that the secondary cells can be disposed side by side at regular intervals in the casing. When the casing is made of metal, it is necessary to keep adjacent secondary cells electrically insulated from each other. Therefore, the outer surface of each secondary cell is covered with an electrically insulating film or sheet (e.g. see Japanese Patent Publication No. JP 2000-348696A and Japanese Patent Publication No. JP 2002-15716A).
The number of secondary cells, that is, the number of sub-chambers in the casing is however decided on the basis of the electric power for driving a subject. For this reason, it is necessary to produce casings in accordance with subjects different in driving power.
Moreover, it is troublesome to cover the outer surface of each secondary cell with an electrically insulating film or sheet. That is, electrode terminals of adjacent secondary cells need to be electrically connected to each other. For this reason, it is necessary to avoid covering the electrode terminal portion of each secondary cell when the outer surface of the secondary cell is wound with the electrically insulating film or sheet. Particularly when the shape of the secondary cell is rectangular, winding tension is apt to be concentrated on corners of the secondary cell. For this reason, it is difficult to wind the electrically insulating film or sheet under uniform tension.